This research proposes to test specific hypotheses derived from a general theory that rapid social and cultural change determines a rise in level of blood pressure and in the prevalence of coronary heart disease, these rises representing the response of individuals who, having been deprived of the supports of a traditional way of life, are attempting to adapt to new and only partially comprehended demands of a new and changing situation. In order to accomplish these objectives, the project proposes to take advantage of a "natural experiment" on the U.S. Trust Territory island of Ponape. This Micronesian island has experienced rapid westernization and "modernization" during the period of its American "occupation" beginning in 1945. The specific hypothesis guiding the research is that persons with high levels of cultural ambiguity and incongruity, high need for achievement, and low levels of supportive affiliation with others will have high levels of blood pressure and high prevalence of cardiovascular disease. The Ponapean population is sampled at three different levels of exposure to rapid social and cultural change: the capital city of Kolonia, the intermediate zone of relatively easy access to Kolonia, and the remote zones of the island. Each individual of the sample is rated on indices of the independent variables: cultural incongruity, need for achievement, and affiliative network. Medical examinations have been conducted to establish the dependent variables, level of blood pressure and prevalence of cardiovascular disease, controlling for appropriate risk factors. Anthropological studies aim to document the nature of the changes in Ponapean way of life and to provide the social and cultural frame for the interpretation of the results of the research.